The replication of adenoviral DNA will be pursued in extracts of nuclei of adenovirus infected HeLa cells. Particular emphasis will be placed on the characterization of eukaryotic DNA polymerases capable of catalyzing elongation of primed-templates containing long single-stranded DNA template regions. Proteins involved in the control of replication of PhiX RFI will be studied. The further characterization of the PhiX A coded protein, the DNA polymerase III of E. coli and the dna G protein will be continued.